1. Field of the Invention
The present invention relates to a cutting or parting tool including a disc-shaped base member having a central bore, a plurality of ring segment-shaped cutting regions provided at a circumference of the base member and separated cirumferentially by recesses open at an outer contour of the base member and extending radically through respective cuffing regions, and at least one elongate opening located in a section of the base member which is defined by a respective cutting region and is limited by two imaginary lines extending from the center of the base member and passing through adjacent recesses, respectively, and by the central bore.
2. Description of the Prior Art
For forming slots in a constructional component in which concealed conduits can be buried, masonry slotting tools which have at least two spaced from each other, disc-shaped parting tools, are used. The spacing between the two parting tools depends on the width of a to-be-formed slot. The two parting tools form two, spaced from each other, slots in a constructional component. Then, the web, which remains between the two slots is removed from the constructional component by a suitable break-out tool, and a channel, in which at least one concealed conduit can be laid in, is formed.
A disc-shaped parting tool for use in masonry slotting power tool is disclosed in German publication DE42 43 480. The disclosed disc-shaped parting tool has a disc-shaped base member having a central bore that provides for mounting of the parting tool on a receiving flange of a masonry slotting power tool.
The base member has, at its circumference, a plurality of circular cutting regions separated by recesses which are open at the out contour of the base member.
In addition to the separating recesses, the base member has a plurality of radially extending elongate openings. Each elongate opening is located in a section which is limited by two adjacent separating recesses and the central bore.
During cutting of mineral constructional components with the use of a so-called dry cutting process, the cutting regions are subjected to high temperatures and to formation of a large amount of cuttings. The removal of the cuttings is effected upon rotation of a parting tool in a direction opposite to the cutting direction, by a surrounding air that flows through the elongate openings which are formed in the space between the cutting regions and the central bore. When a particular large amount of cuttings is formed, the cuttings cannot be removed sufficiently rapidly from the intermediate space between two parting tools as a sufficiently high circulation of air through the elongate openings cannot be obtained. The reason for this is a large circumferential distance between separate elongate openings.
With an increased amount of cuttings, the cutting region heats up to a very large degree. The reduced air circulation leads to a thermal overstress and damage of the parting tool.
Accordingly, an object of the present invention is to provide a disc-shaped parting tool which would insure a good and reliable removal of cuttings without a thermal overstress of the parting tool.
This and other objects of the present invention which will become apparent hereinafter, are achieved by providing in each section of the base member, which is limited by two adjacent separating recesses and the central bore, at least one elongate opening extending radially along a section of a spiral line which starts from the center of the base member.
In accordance with the present invention, the elongate openings extend not only radially but also in the circumferential direction, forming, in the circumferential direction, closely following each other, air entry regions through which air can be fed in the intermediate space formed by two parting tools in large amounts. The large amount of air, which is fed to remove the cuttings, also insure a very good cooling of the parting tools.
A particularly good air circulation and removal of cuttings from the intermediate space, which is formed by two, spaced from each other, disc-shaped parting tools, is advantageously achieved when a tangent to a central region of a longitudinal extent of an elongate opening forms with the radius of the base member an angle from 7xc2x0 to 15xc2x0. A particular good removal characteristics are achieved with the angle, which is formed by the tangent and the radius, being equal 11xc2x0.
An increased feeding of the air in the vicinity of the cutting region and, thus, a good cooling of the parting tool is advantageously achieved when the width of the elongate openings, measured transverse to its longitudinal extent, increases toward the outer contour of the base member.
Preferably, in at least one section of the base member, which is limited by two separating recesses and the central bore, two elongate openings are provided. This further increases the amount of air entering the intermediate space between the two parting tools. This further contributes to an increased removal of cuttings and cooling of the parting tool. For manufacturing reasons, the two elongate openings are formed substantially with the same size.
In order to be able to achieve a very good air circulation, advantageously, a circumferential distance between the two elongate openings located in the same section of the base member is smaller than a circumferential distance between two adjacent elongate openings of two adjacent base member section.
Accumulation of cuttings in the separating recesses of the base member is prevented when, advantageously, the circumferential width of a recess increases toward the central bore. The cuttings which, e.g., accumulate in the mouth region of a recess, are pressed radially into an expanded portion of the recess by further cuttings. In the expanded portion of the recess, the cuttings have no support and fall through.
In the parting tools, the cutting region is formed or is defined by circumferential region of the base member which is filled with diamond grains. The cutting region can also be formed of separate segment-shaped cutting bodies formed of diamond grains and a matrix material. The separate cuttings bodies can be attached to the base member by soldering, welding, and the like.
The elongate openings can also so be formed that, while being separate from each other, they overlap each other in the circumferential direction of the base member.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction its mode of operating, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment, which read with reference to the accompanying drawings.